Sheet handling apparatus and image forming apparatus

Abstract

When the rear end of a sheet bundle S is brought to reach the clamping portion between a rocking roller and a rear end aligning wall by conveyance means, the individual timings, at which the rocking roller and the rear end aligning wall move to the escape position, are controlled to drop said sheet bundle S onto a stack tray, and then the rear end aligning wall is moved from the escape position to the support position thereby to register the rear end of the sheet bundle S dropped on the stack tray.

1. A sheet handling apparatus comprising:
 a stack tray which stacks a sheet or a sheet bundle; 
 support unit capable of moving selectively to a support position at which it supports the lower face of the sheet or the sheet bundle, or an escape position at which it escapes from the lower face of said sheet or said sheet bundle; and 
 change-over control portion which changes the support position and the escape position of said support unit; 
 wherein said change-over control portion moves said support unit from the support position to the escape position at a first moving velocity thereby to drop the sheet or the sheet bundle onto said stack tray, and then moves said support unit at a second moving velocity from the escape position to the support position thereby to push the sheet or the sheet bundle toward said stack tray so as to align the sheet or the sheet bundle, and 
 wherein said second moving velocity is slower than said first moving velocity. 
 
   
   
     2. A sheet handling apparatus according to  claim 1 ,
 wherein said change-over control portion includes a detection sensor which detects the movement of the sheet or the sheet bundle thereby to control the movement of said support unit on the basis of the detection result of said detection sensor. 
 
   
   
     3. An image forming apparatus comprising:
 a sheet handling apparatus according to  claim 2 ; and 
 an image forming portion which forms an image on a sheet to be conveyed to said sheet handling apparatus. 
 
   
   
     4. A sheet handling apparatus according to  claim 1 , further comprising:
 a handling tray capable of stacking a plurality of sheets temporarily on the upstream side of said stack tray in the sheet conveyance direction thereby to handle the sheet or the sheet bundle; and 
 a conveyance portion capable of conveying the sheet or the sheet bundle from said handling tray toward said stack tray, 
 wherein said support unit supports the lower face of the sheet or the sheet bundle which is conveyed by said conveyance portion. 
 
   
   
     5. A sheet handling apparatus according to  claim 4 , further comprising:
 at least one aligning unit which aligns the sheets stacked on said handling tray and a staple unit which staples the sheet bundle. 
 
   
   
     6. A sheet handling apparatus according to  claim 4 ,
 wherein said conveyance portion can move selectively to the support position for supporting the upper face of the sheet or the sheet bundle, or to the escape position escaped from the upper face of the sheet or the sheet bundle. 
 
   
   
     7. A sheet handling apparatus according to  claim 1 , further comprising:
 a sheet returning member which returns the sheet or the sheet bundle toward said support unit each time they are discharged onto said stack tray. 
 
   
   
     8. A sheet handling apparatus according to  claim 1 ,
 wherein said stack tray includes a substantially horizontal sheet stacking face. 
 
   
   
     9. A sheet handling apparatus according to  claim 1 ,
 wherein said stack tray can ascend and descend. 
 
   
   
     10. An image forming apparatus comprising:
 a sheet handling apparatus according to  claim 1 ; and 
 an image forming portion which forms an image on a sheet to be conveyed to said sheet handling apparatus. 
 
   
   
     11. An image forming apparatus comprising:
 an image forming portion which forms an image on a sheet; 
 a stack tray which stacks the image-formed sheet or sheet bundle; 
 support unit capable of moving selectively to a support position at which it supports the lower face of the image-formed sheet or the sheet bundle, or an escape position at which it escapes from the lower face of said sheet or said sheet bundle; and 
 change-over control portion which changes the support position and the escape position of said support unit, 
 wherein said change-over control portion moves said support unit from the support position to the escape position at a first moving velocity thereby to drop the sheet or the sheet bundle onto said stack tray, and then moves said support unit at a second moving velocity from the escape position to the support position thereby to push the sheet or the sheet bundle toward said stack tray so as to align the sheet or the sheet bundle, and 
 wherein said second moving velocity is slower than said first moving velocity. 
 
   
   
     12. An image forming apparatus according to  claim 11 ,
 wherein said change-over control portion includes a detection sensor which detects the movement of the sheet or the sheet bundle thereby to control the movement of said support unit on the basis of the detection result of said detection sensor. 
 
   
   
     13. A sheet handling apparatus comprising:
 stack tray which stacks a sheet or a sheet bundle; 
 a first support unit capable of moving selectively to a support position at which it supports the upper face of the sheet or the sheet bundle, or an escape position at which it escapes from the upper face of said sheet or said sheet bundle; 
 a second support unit capable of moving selectively to a support position at which it supports the lower face of the sheet or the sheet bundle, or an escape position at which it escapes from the lower face of said sheet or said sheet bundle; 
 change-over control portion which changes the support position and the escape position independently of said first support unit and said second support unit; and 
 wherein said change-over control portion controls the individual timings, at which said first support unit and said second support unit move from the support position to the escape position, thereby to drop the sheet or the sheet bundle onto said stack tray, and then moves said second support unit from the escape position to the support position thereby to push the sheet or the sheet bundle toward said stack tray so as to align the sheet or the sheet bundle. 
 
   
   
     14. A sheet handling apparatus according to  claim 13 ,
 wherein the change-over control portion controls the timing at which said first support unit moves to the escape position so that it becomes simultaneous with or earlier than the timing at which said second support unit moves to the escape position. 
 
   
   
     15. An image forming apparatus comprising:
 a sheet handling apparatus according to  claim 14 ; and 
 image forming portion which forms an image on a sheet to be conveyed to said sheet handling apparatus. 
 
   
   
     16. A sheet handling apparatus according to  claim 13 , further comprising:
 a handling tray capable of stacking a plurality of sheets temporarily on the upstream side of said stack tray in the sheet conveyance direction; and 
 a conveyance portion capable of conveying the sheet or the sheet bundle from said handling tray toward said stack tray, 
 wherein said first support unit includes said conveyance portion, and 
 wherein said second support unit supports the lower face of the sheet or the sheet bundle which is conveyed by said conveyance portion. 
 
   
   
     17. A sheet handling apparatus according to  claim 16 , further comprising:
 at least one of aligning unit which aligns the sheets stacked on said handling tray and a staple unit which staples the sheet bundle. 
 
   
   
     18. A sheet handling apparatus according to  claim 13 ,
 wherein said second support unit has a lower elastic force in the supporting state than that of said first support unit in the supporting state. 
 
   
   
     19. An image forming apparatus comprising:
 a sheet handling apparatus according to  claim 13 ; and 
 image forming portion which forms an image on a sheet to be conveyed to said sheet handling apparatus. 
 
   
   
     20. An image forming apparatus comprising:
 image forming portion which forms an image on a sheet; 
 stack tray which stacks the image-formed sheet or sheet bundle; 
 first support unit capable of moving selectively to a support position at which it supports the upper face of the image-formed sheet or sheet bundle, or an escape position at which it escapes from the upper face of the sheet or the sheet bundle; 
 second support unit capable of moving selectively to a support position at which it supports the lower face of the sheet or the sheet bundle, or an escape position at which it escapes from the lower face of said sheet or said sheet bundle; and 
 change-over control portion which changes the support position and the escape position independently of said first support unit and said second support unit, 
 wherein said change-over control portion controls the individual timings at which said first support unit and said second support unit move from the support position to the escape position, thereby to drop the sheet or the sheet bundle onto said stack tray, and then moves said second support unit from the escape position to the support position thereby to push the sheet or the sheet bundle toward said stack tray so as to align the rear end of the sheet or the sheet bundle. 
 
   
   
     21. An image forming apparatus according to  claim 20 ,
 wherein said change-over control portion includes a detection sensor which detects the movement of the sheet or the sheet bundle thereby to control the movements of said first support unit and said second support unit on the basis of the detection result of said detection sensor.